Monitoring Structure Development in Semiconducting Polymer Thin Films by In situ GIWAXS of during blade coating

The field of organic electronics has seen significant advancements in the last decades due to the potential for large-area and cost-effective device fabrication, which results from the fact that these devices can be readily processed from solutions (as inks). It is well-known that the device performance is intrinsically linked to the packing characteristics of semiconducting polymers (i.e. their microstructure), which is formed during solidification via crystallization. Despite its utter importances, understanding how microstructure of polymer semiconductors develops during processing remains challenging. This study aims to explore the microstructure development of high-performing semiconducting polymer D18 for solar cells during thin-film formation. A portable, remotely controlled blade-coating setup will be installed at the NCD-SWEET beamline, enabling in situ acquisition of GIWAXS data during the formation of thin films. The crystallization process of D18 will be investigated under varying conditions, including different solvents (chlorobenzene, o-xylene, dichlorobenzene, chloroform, etc.), different blade velocities, and substrate temperatures (e.g. 25 ºC and 50 ºC). These experiments will provide critical insights into the solidification mechanisms of polymer thin films, advancing the understanding of structure formation in organic electronic materials.